1. Field of the Invention
This present invention relates to a method for image correction, and more particularly to a method for correcting the magnification in a photographic device.
2. Description of the Prior Art
Before capturing an image of an object, it is important to perform the correct preliminary processes on a photographic device. Due to the inaccuracy of the photo mechanism in the photographic device during the manufacturing and assemblage thereof, there is a difference in dimension between the image captured by the photographic device and the objective. In the prior art, a mark disposed in the photographic device is employed for correcting the above-mentioned difference between the captured image and the objective. While the photographic device captures the image from an object, the photographic device will also capture the image of the mark. The magnification in the photographic device is corrected by the image of the above-mentioned mark in the photographic device. For example, referring to FIG. 1, in a scanner according to the prior art, a mark 20 is disposed in one side of the scanning window 30 of the scanning plate 10. The above-mentioned scanner will scan the object and the mark 20 at the same time, and the magnification in the scanner is corrected by comparing the dimension of the image captured from the mark 20 and the real dimension of mark 20.
However, in the above-cited correcting method, it is very inconvenient and inefficient that the scanner has to scan mark 20 in order to correct the magnification of the scanner after every image captured. On the other hand, in the above-mentioned correcting method, the scanner has to occupy a part where the mark 20 is disposed. Hence, it is important to develop an efficient method for correcting the magnification in a photographic device to output the image with the correct dimensions.